The aim of the study was to highlight the factors that contribute to professional health assessment work, in order to develop health assessment work by telephone in primary care. The research questions for this study ware: What factors contribute to professional healthcare assessment work by phone? How can the health assessment process be developed? The method was inspired by action research, with both a quantitative and qualitative approach. To get comprehensive results, three different data collection methods were used in this study. First statistics were collected about how the patients were referred. Nurses working with healthcare assessment tasks also filled in a questionnaire regarding health assessment work by telephone. Thereafter interviews with leading employees within the organization were conducted. Data were analyzed using descriptive statistical methods and content analysis. Based on the findings a model was designed that highlights the factors that contribute to the professional healthcare assessment work. A developmental communications tool was designed with the aim of getting a more structured and uniform work in health assessment. The communication tool was evaluated by both nurses and the management within the organization and thereafter designed into the final format. The results of the study show that health assessment work is demanding and it is sometimes difficult to determine the severity according to the symptoms described by the care-seekers. The skills and work experience of the nurses is clearly decisive for the health assessment quality. The personality of the nurses also has an important role in communicating with the care-seekers.